Children of all ages will have something more than just Santa Claus to watch the skies for this week with tonight’s great conjunction of Jupiter and Saturn. While Jupiter and Saturn align with each other approximately every 20 years, it has been nearly 400 years since they have been this close to each other and almost 800 years since the alignment has occurred at night. The timing of the conjunction is all the more special since it occurs on the solstice and just days from Christmas. Some astronomers as far back as the 17th century hypothesized that the Star of Bethlehem, which guided the three wise men to the birthplace of Jesus, was the occurrence of a conjunction similar to tonight’s event.
“Conjunctions like this could happen on any day of the year, depending on where the planets are in their orbits,” said Henry Throop, astronomer in the Planetary Science Division at NASA Headquarters in Washington. “The date of the conjunction is determined by the positions of Jupiter, Saturn, and the Earth in their paths around the Sun, while the date of the solstice is determined by the tilt of Earth’s axis. The solstice is the longest night of the year, so this rare coincidence will give people a great chance to go outside and see the solar system.”
The planets will appear low in the southwest in the hour after sunset and will appear just a tenth of a degree apart. While both planets will be easy to spot with the naked eye, gazers with access to a set of binoculars or a small telescope will also be able to see each planet’s moons.
According to Wiley Butler, NWS Cooperative Observer, the weather for tonight calls for patchy fog after midnight. Otherwise, partly cloudy, with a low around 39. Southwest wind around 5 mph becoming calm in the evening.